High-temperature and Corrosion Behavior of Nitrate Nitrite Molten Salt Mixtures Regarding their Application in Concentrating Solar Power Plants

We deeply investigated the chemical reaction network of molten nitrate / nitrite salt mixtures at high temperatures (> 450 °C) and proved530 °C as maximum operating temperature of HITEC® in CSP application with potential for further temperature increase by implementation of technical measures. Particularly the level of oxide ion concentration and the gas atmosphere havesignificant effects on thermal stability and corrosion behavior. It could be shown that the corrosive depletion of standard steels is within technical limits up to the thermal stability limit of the salt mixture. Low chloride concentration of the melt is crucial for low corrosivity.